Circuit breaker switch unit



Nov. 17, 1953 Filed Dec. 28. 1949 R. T. CASEY CIRCUIT BREAKER SWITCH UNIT 2 Sheets-Sheet l V Inventor: Robert. T. Casey.

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R. T. CASEY- CIRCUIT BREAKER SWITCH UNIT Nov. 17, 1953 2 Shaets-Sheet 2 Filed Dec. 28. l949 lnventorz- Robert, T. Cases.

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Patented Nov. 17, 1953 CIRCUIT BREAKER SWITCH UNIT Robert '1. Casey, Bristol, Conn., assignor, by

mesne assignments, to General Electric Company, a corporation of New York Application December 28, 1949, Serial No. 135,378 11 Claims. (Cl. 200-116) My-invention relates to electric switch mechanismg'which is operable manually and particularly .to a mechanism which can be installed as a unit to be associated with an overload release of an automatic circuit breaker.

Such circuit breakers are provided with circuit making and breakingelements which are operable by means of push buttons or levers and are also adapted to open a circuit or circuits automatically in case of an overload and are usually so constructed that they can be reset manually. One object of the present invention is to providea simple, inexpensive and reliable mechanism for use in a circuit breaker by which the circuit or circuits may be opened and closed manually and by. which the circuits will open automatically in case the overload release of the circuit breaker is actuated.

Another object is to provide for the manual resetting of the circuit breaker after an automatic breaking of the circuit.

\ Another object is to provide a switch unit which is sensitive in operation and yet free from danger of release due to shock.

Another object is to provide a switch unit which can be adapted for use in either a push button orrlever-actuated type of circuit breaker.

Another object is to provide a switch unit whose operating means will-assume a distinct position upon automatic opening of the contacts, to furnish an indication of such automatic opening.

iAnother object is to provide a circuit breaker which is sensitive to automatic action but reliable.

Fig. 1 is a fragmentary longitudinal sectional view and side elevation showing a push-buttonactuated type switch with the parts of the switc in the closed circuit position.

Fig. 1a is a fragmentary plan view showing the relation of the improved mechanism to a circuit breaker. J

Fig. 2 is a fragmentary side view showing parts in the automatically tripped position.

Fig. 3 is a similar fragmentary side view showing the parts in the manually opened position.

Fig. 4 is an end view of a fragment of the operating mechanism, omitting the push button oper- Fig. 7 is a side view and partial section showing modified details of a push button actuated type switch showing the parts in the closed circuit position.

Fig. 8 is a fragmentary side view of the parts shown in Fig. 7 but showing the parts in the automatically tripped position.

Fig. 9 is a view similar to Fig. 8 showing the parts in the manually open circuit position. I

Fig. 10 is a fragmentary end view of parts of the mechanism of Figs. 7 to 9, inclusive, omitting the push button operators.

Fig. 11 is a fragmentary perspective view of the latching means of Figs. 7 to 10, inclusive.

In the form shown in Fig. l, the base iof the circuit breaker is formed of insulatingmaterial and mounts the circuit terminals and switch contact elements and the switch actuating unit. The terminal 2 is connected toa stationary switch contact 3 and the movable switch contact 4 it carried by a spring arm 5 which is supported by the terminal 6.

The switch actuating unit has a frame I whose side plates have feet 8, 8 secured to the base in any suitable manner. The operating arm or lever 9 has pivot pins Ill forming a pivot supported and guided in openings I8 in the'side plates and is connected by an insulating link Ii to the switch contact arm 5. r

A lever i2 is pivoted at l3' between theside plates and has a projecting pin or roller it against which the arm 9 is pulled by spring i5 which connects the eye iii of the arm 9 to a pin l'l supported in the frame I.

Lever I2 has an extension i9 to which'the actuating push buttons 20 and 2i are connected. These push buttons are guided in open'ingsin a face plate member 22 which is supported by a frame 23 connected to frame 1 in any suitable manner. The rocker 24 pivoted at 25 in frame 23 has its opposite ends connectedto the push'buttons in any suitable manner and is connected by links 26 to the extensions is of lever I2.

It will be seen that the spring I5 exerts a diagonal pull on the arm 9, one component biasing the arm vertically downward against the roller or projection it on lever l2 and the other component biasing the arm horizontally (as viewed in the drawing). When button is depressed. it tilts rocker 24, raises link 26 and turns lever l2 anticlockwise with movement of the projection ll longitudinally of the arm 9 toward the left. Thereupon the spring 15 pulls the arm 5 so that the projection i4 slides along the inclined cam portion 21 of arm 9 from the position oi'Fig. 1 to that of Fig. 3, thus opening the circuit. It

3 will be seen that the cam portion 21 intermediate the ends of the arm 9 is offset transversely with respect to the pivot l9. Depression of button III reverses the action and closes the circuit.

As shown in the drawing, the projection H is held by the arm 9 and spring I! in each of the positions of Figs. 1 and 3. In Fig. 1 the projection ll has been moved to a position past the outside or right-hand bend in the arm 9 so that the force of the spring I! is-applied to the projection ll along a line passing substantially to the right of the pivot II for the lever i2. In Fig. 3 the projection H is held by being seated in the inside or left-hand bend in the arm I.

A latch 30 is pivoted at 3| in the frame and normally engages the end of arm 9. Strip spring 92 resiliently holds the latch and the pivoted end of arm 9 in the positions of Figs. 1 and 3. This spring 32 is of approximately S-shape and has one end Iii fixed to the frame and its remote end 9| arranged in the path of movement of a part of the overload release member 35. This latter member is of insulating material and is hinged at 96 to a stationary support 31 carried by the base. A spring 38 in the operating condition pulls the release member against the stationary shoulder 99 of the base with its finger 40 close to the bimetal overload current-responsive strip 4 I.

when the overload actuated member ll is brought into pla by an overload or predetermined high current in the circuit, it engages the finger All of the release member and tilts it about its pivot 36 and the spring 38 snaps it over so that the member 3! strikes the end 34 of the release spring.

As the end 94 of the release spring 32 is pressed by the member 95, and moved toward the righthand as seen in Figs. 1 to 3, the spring itself is distorted so that its intermediate portion passing through jaws I! of the latch 30 is caused to move upwardly so as to release the latch, which in turn releases the end of arm 9 so that the spring I! can tilt the arm 9 about the roller I4 and move the parts to the tripped position of Fig. 2 intermediate the normal on" and oil position.

To reset the parts from the automatically tripped position of Fig. 2, button 2| is depressed so that the end 43 of lever l2 presses against the tip 34 or the spring latching member and an edge of lever 12 engages the shoulder N on arm I. The arm 9 is thus shifted until the pivot pins III are returned to the bottom of the slots II as shown in Fig; 3, the latch 30 being turned clockwise somewhat to its latched position on the spring 32 by the lower left-hand end of the arm 9. The button 20 may then be depressed to close the circuit.

Referring to the preferred form, it will be seen that in moving from the open circuit position of Fig. 3 to the closed circuit position of Fig. 1. operating arm 9 first pulls switch arm upward- 1y by means of insulating slide ll, until movable contact 4 engages staitonary contact 3.

Arm 9 continues its upward movement for a very short distance after the contacts are closed, thereby bending switch arm 5 slightly as shown in Fig. 1. thereby insuring the maintenance of good contact pressure, switch arm I being made of resilient material.

In order to operate properly, the arm 9 and the latch 89 are relatively rigid but the latch operating member I: is formed of spring material.

It will be noted that the upper end of spring 4 which permits the proper coaction with the latch member and also permits the resetting of the release member when the operating arm 9 is reset.

The opening it has a narrow slot-like portion extending vertically with respect to the horizontally movable arm 9 so as to normally guide the pivot pins l9 and oppose longitudinal movement of the arm 9 by the pull of the spring I! (see Figs. 1 and 3). The upper part of this opening I9 is enlarged so as to permit the floatingly mounted arm to move longitudinally toward the right-hand (see Fig. 2) when the latch 30 releases the end of the arm 9, when the spring release member 32 is retracted by the pressure of member 35.

It will be observed that in moving fromthe closed position of Fig. 1 to the tripped position of Fig. 2, the arm 9 when released is first pivoted clockwise by the spring I5 about the roller it to move the pins III upward out of the narrow vertical slot portions in the lower ends of the openings II, at which point the arm 9 is moved longitudinally toward the right both by the normal longitudinal component of the spring I! and the increase in this component effected by the clockwise pivoting of the arm on the projection ll. Thereafter the cam portion 21 slides over the projection l4 thereby still further increasing the longitudinal force on the arm 9 toward the right to give more positive longitudinal movement of the arm, the arm pivoting clockwise about the pins l9, and at the same time applying an oppositely directed force to the roller ll, i. e., a

counter-clockwise force to the lever l2 about the pivot iii. The arm 9 comes to rest longitudinally when the pins IU engage the right-hand wall of the upper enlarged part of opening 18 and the lever l2 comes to rest in the intermediate tripped indicating position of Fig. 2 by the seating of the roller is in the inside bend in the arm. In the event that the lever I2 is held in the position of Fig. 1 by continued pressure on the button 20, the arm 9 is pivoted by the spring it about the projection l4 until the pins in engage the upper end of the opening I! thereby to provide for substantially complete open circuit separation of the contacts.

Fig. 6 shows the invention as applied to a leveractuated type of switch mechanism. In this form, the frame I supports an operating arm I, a spring IS, a latch 30 and a spring release member 92 which are similar to the corresponding parts just described. I have also shown a lever I! which corresponds with lever i2 previously described. This lever l2 extends from the frame and is provided with a handle or finger piece II by which the switch is manually actuated and reset in the same manner as by the push buttons.

Figs. 6 and 6a show an arm 41 formed as a part of lever I! which serves to engage the upper inclined edge ll of arm 9 and force the arm I to an open circuit position when the lever I2 is moved to the 0115" position.

In the form shown in Figs. 7 to 11, inclusive, I have shown the switch mechanism substantially the same as that shown in Figs. 1 to 5, inclusive, with the exception of the method of hinging the actuating arm. The hinge pins II in this case are supported by links 99' which are hinged at Ii in the opposite side plates of the frame I.

The lever I2" is hinged at II and carries the projecting pin or roller ll which supports the arm 9' adjacent the cam portion 21'. The spring ll biases the arm r downwardly and toward the right as shown in Figs. 7 to 9, inclusive. The push buttons 20 and 2| are guided in the face plate 22' of the frame 23' and actuate a rocker 24' pivoted at 25' to the link 26 which is connected to the extension I! of the actuating lever. The elongated substantially s-shaped spring strip 32' is anchored at 33' and has the terminal ears 34 adapted to be engaged by the release member 35 in case of an overload-as previously described. The horizontal ar'm of the spring 32' is notched at 42.2: to receive the jaws 42' of the operating arm 9' as shown in Fig. 11. This interlock holds the left hand end of operating arm 9' in a manner similar to the action previously described so that the opening and closing movements of the arm 9' is effected manually in the same manner as that of Figs. 1 to 3, inclusive. In this case, the release spring is provided with an upturned lug a: which is engaged by the edge of the actuating lever I!" in resetting the switch after automatic trip.

The automatic trip takes place when the release member 35 engages'one of the ears 34 and releases the spring 32' from the interlock. This permits the spring 15' to move the arm 9' which slides over the projection H and causes the left hand end of the arm 9' to move longitudinally forward from the position of Fig. 7 to that of Fig. 8 at which time the hinge pivots 3| of the links 30' slide downwardly in the inclined slots 50, the links acting as a latch to normally hold the arm 9' in position for manual operation.

It will be seen that the links 30' are mounted on the outside of the frame plates and have offset portions which pass through the openings I8 to engage the hinge pins I of the arm 9.

A supplemental spring may be provided to bias the connecting slide II upwardly as shown in Fig. 7 so that the operating arm 9' only engages the slide when the switch is thrown off," when it will push the slide downwardly to open circuit position against the bias of this supplemental spring. This method allows the arm 9 or 9 to be free of any contact pressure loading and reduces friction against horizontal movement of the actuating arm in tripping since the vertical component of the spring l5 or I5 is the only force causing such friction and it acts very close to the pivot point 14.

It is the horizontal component of the pull of the spring I5 which serves to slide the arm 9 forward on automatic tripping and the vertical component moves the arm downwardly to open the circuit. It is therefore possible to provide for the proper distribution of the force of spring l5 between these two functions merely by suitably arranging the angle of pull of the spring with respect to the horizontal line of movement of arm 9. It is thus possible to minimize the pressure of the arm 9' on the spring 32' at its latching connection. For this purpose the horizontal component of the tension of spring I5 is arranged to be just sufficient to overcome the latching engagement and overcome the friction of the parts and cause movement of the arm at the proper time. This is possible regardless of the vertical forces required to ensure positive separation of the switch contacts in opening the circuit.

Fig. 5a shows a simplified method of supporting the arm 9' adjacent the connection with the latching member 32'.

Here the links 30' have been omitted and the pivot pins or bearings I0 are guided in horizontal slots I8" adjacent the latching connection between arms 9' and. the releasing spring 32'.

The S-shaped latching and release spring being resilient throughout its length and being light in weight absorbs the effects of shocks'and vibrations so that it is very diilicult to cause accidental tripping by reason of shocks 0r vibrations.

When the switch is tripped automatically the operating member takes up a position intermediate the on and off" position and thus serves as an indication of the condition of the circuit.

I claim:

1. In a circuit breaker having a stationary switch contact and a movable switch contact and an overload actuated member, a unit for actuating said movable switch contact comprising a U-shaped frame having opposed openings in its side walls, an actuating lever hinged to and between the side walls of the frame, an operating arm floatingly connected with said lever and at one end with the edges of the openings, the other end of the arm being operatively connected to the movable switch contact, a spring normally urging movement of the operating arm, a latch hinged between the side walls of the frame and interlocked with the other end of the arm for holding the arm against movement by said spring, manually operable means extending externally of the frame for actuating said lever and for permitting the spring to move the arm and means associated with said latch for shifting said interlock upon an overload including a spring member interlocked with said latch and having a free end to be engaged by an overload actuated member.

2. A circuit breaker comprising a fixed contact and a movable contact, a manually movable member for controlling movement of said contacts into and out of engagement, a floating actuating lever between said manual member and said movable contact and having a pivotal engagement with said manual member, spring means always biasing said floating lever for engagement with said manual member, a. member movable in response to the effect of an abnormal current to release said floating lever, said release member acting as a support for said floating lever whereby said floating lever pivots about its point of engagement with said releasable member during manual engagement and disengagement of said contacts, said floating lever rotating about said point of pivotal engagement with said manually operable member upon release of said release member, and means for guiding said floating lever in its movements, so as to permit said member to move to its automatically tripped position, but to prevent it from returning to its original position thereafter without a positive manual resettingoperation, said floating lever having oppositely disposed projections adjacent the end thereof about which it normally pivots, and means for guiding said floatinglever in its movements, said means including side walls on either side of said floating lever and generally arcuate slots in said side walls, said projections being guided in said slots, said slots having an enlarged portion adapted to trap said projections therein upon automatic release of said circuit breaker whereby the movement of said parts is arrested so as to cause said manually movable member to assume a position intermediate its "on" and "off positions for the purpose of indicating its automatically tripped condition.

3. A circuit breaker comprising cooperating switch contacts, an arm having one end connected to move one of said contacts and formed with a. transverse cam portion intermediate its ends, means'for pivotally supporting the other aosa'rss end or said arm and providing for longitudinal movement of said arm in a predetermined direc-: tion, current-responsive latching means for securing said pivoted end in a predetermined pivoted position, an operating projection mounted for movement longitudinally of said arm, and a spring connected to said arm for biasing said arm about said pivoted end against said projection to an open circuit position so that movement of mid projection in said predetermined direction over said cam portion moves said arm about said pivoted end to a closed circuit position and release of said pivoted end by said current-responsive latching means effects movement of said cam portion over said projection with longitudinal movement of said am by said spring in said predetermined direction to an open circuit position.

4. A circuit breaker comprising cooperating switch contacts, an arm having one end connected to move one or said contacts and formed with a transverse cam portion intermediate its ends, means for pivotally supporting the other end of said arm and providing for transverse movement of said arm and for longitudinal movement or said arm in a predetermined direction, current-responsive latching means for securing said pivoted end in a predetermined pivoted position, an operating lever having a projection, and a spring connected to said arm for biasing said arm about said pivoted end against said projection to an open circuit position so that movement or said projection in a predetermined direction over said cam portion moves said arm about said pivoted end to a closed circuit position and release of said pivoted end by said currentresponsive latching means effects movement of said cam portion over said projection with longitudinal movement of said arm by said spring in said predetermined direction to an open circuit position.

5. A circuit breaker comprising cooperating stationary and movable switch contacts, an arm provided with a pivot at one end and having an intermediate cam portion ofiset transversely of said pivot, an operating connection between the other end of said arm and said movable contact, means supporting said pivot for movement of said pivot and said arm both transversely and longitudinally of said arm from one position to another, means for securing said pivot in one of said positions, an operating member intermediate the ends or said arm mounted ior movement longitudinally of said arm, a spring for biasing said arm about said pivot against said operating member to an open circuit position so that movement of said operating member over said cam portion moves said arm about said pivot to a closed circuit position and continued movement oi! said operating member to a position past said cam portion secures said arm in said closed position, and means responsive to the current in said contacts for releasing said pivot for movement to its other position upon the occurrence of a predetermined high current to effect movement of said cam portion over said operating member with pivotal and longitudinal movement of said arm by said spring to an open circuit position.

6. A circuit breaker comprising cooperating switch contacts, an arm having one end connected to move one or said contacts and formed with a transverse cam portion intermediate its ends with inside and outside bends at the respective ends of said cam portion, means for pivotally ing for movement of said pivot for transverse and longitudinal movement or said am, currentresponsive latching means for securing said pivoted end in a predetermined pivoted position, an operating projection mounted for movement longitudinally or said arm and a spring connected to said arm for biasing said arm about said pivoted end against said projection to an open circuit position so that movement of said projection over said cam portion moves said am about said pivoted end between closed and open circuit positions with said projection seated in said inside bend in said closed position and release of said pivoted end by said current-responsive latching means eitects movement or said cam portion over said projection with pivotal and longitudinal movement oi said arm by said spring to an open circuit position and movement or said projection back to an intermediate position in which said projection is seated in said inside bend.

7. A circuit breaker comprising cooperating stationary and movable switch contacts, an arm provided with a pivot at one end and having an intermediate cam portion offset transversely oi. said pivot with inside and outside bends at the respective ends of said cam portion, an operating connection between the other end of said arm and said movable contact, means supporting said pivot for movement of said pivot and said arm both transversely and longitudinally of said arm from one position to another, means for holding said pivot in one of said positions, a spring for biasing said arm about said pivot to an open circuit position, an operating member engaged by said arm mounted for movement longitudinally of said arm over said cam portion to move said arm about said pivot between open and closed circuit positions, said operating member seated in said inside bend to hold said arm in said open circuit position and moved to a position past said outside bend to hold said arm in said closed circuit position, and means responsive to the current in said contacts for releasing said pivot for movement to its other position upon the occurrence of a predetermined high current to effect movement or said cam portion over said operating member with pivotal and longitudinal movement or said arm by said spring to an open circuit position and movement or said operating member back to an intermediate position with said operating member seated in said inside bend.

- 8. A circuit breaker comprising cooperating stationary and movable switch contacts, an arm provided with a pivot at one end and having an intermediate cam portion oil'set transversely 0! said pivot with inside and outside bends at the respective ends of said cam portion, an operating connection between the other end of said arm and said movable contact, supporting members on opposite sides or said arm having enlarged openings for the ends of said pivot to provide for movement of said pivot and said arm both transversely and longitudinally of said arm from one position to another, latching means for holding said pivot in one of said positions, a spring for biasing said arm about said pivot to an open circuit position, an operating member engaged by said arm pivotally mounted intermediate the length or said arm for movement longitudinally of said arm over said cam portion to eflect movement 01' said arm about said pivot between open and closed circuit positions with said operating member seated in said inside bend when said arm i in said open circuit position and moved to a supporting the other end or said am and provid- 15 position past said outside bend to hold said am in said closed circuit position, and means responsive to the current in said contacts for operating said latching means to release said pivot for movement to its other position upon the occurrence of a predetermined high current to eiTect movement of said cam portion over said operating member with pivotal and longitudinal movement of said arm by said spring to an open circuit position and movement of said operating member back to an intermediate position with said operating member seated in said inside bend.

9. A circuit breaker comprising a fixed contact, a resiliently mounted movable contact, an arm having a movable end connected to move said movable contact and an intermediate transverse cam portion, means for pivotally supporting the opposite end of said arm and providing for longitudinal movement of said arm in a predetermined direction from said pivoted end toward said movable end, latching means for holding said end in a predetermined position, an operating lever having one end pivotally mounted at a point intermediate the length of said arm, a projection on "said operating lever, a spring biasing said arm about its pivot against said projection so that movement of said operating lever moves said projection over said cam portion thereby to move said arm about said pivot between closed and open circuit positions, saidspring bein arranged to apply a component of force to said arm biasing said arm longitudinally in said predetermined direction, current-responsive means for operating said latching means to release said pivot upon the occurrence of a predetermined high current whereupon said arm is moved 1ongitudinally by said spring toefiect movement of said cam portion over said projection with pivotal movement of said arm to an open circuit position, and a projection on said arm engaged by said operating lever to move said arm longitudinally in an opposite direction to return sa'id pivoted end to said predetermined position.

'10. A circuit breaker comprising a fixed contact, a resiliently mounted movable contact, an arm having a movable end connected to move said movable contact and an intermediate transverse cam portion, means for pivotally support- \ing the opposite end' of said arm and providing for transverse and longitudinal movement of said arm, latching means for holding said end in a predetermined position, an operating member having one end pivotally mounted at a point intermediate the length of said arm, a-projection on said operating member, a spring biasing said arm about its pivot against said projection so that movement of said operating lever moves said projection over said cam portion thereby to move said arm about said pivot between closed and open circuit positions, said spring being arranged to apply a component of force to said arm biasing said arm longitudinally in a direction from said pivoted end toward said movable end, current-responsive means for operating said latching means to release said pivot upon the occurrence of a predetermined high current whereupon said arm is first pivoted by said spring about said projection and then moved longitudinally by said spring to effect movement of said cam portion over said projection with pivotal movement of said arm to an open circuit position.

11. A circuit breaker comprising a fixed-contact, a resiliently mounted movable contact, a pair of substantially parallel supporting plates provided with oppositely disposed openings in adjacent ends including each a transverse slot portion and a communicating longitudinal portion extending toward the opposite ends of said plates,

an arm having a movable end connected to move said movable contact and an intermediate transverse cam portion, a pivot on the opposite end of said arm extending into said openings for slidable and pivotal movement with respect to said supporting plates, latching means for holding said pivot in said slot portions, an operating lever having one end pivotally mounted on said supporting plates at a point intermediate the length of said arm, a projection on said operating lever, a spring biasing said arm about its pivot against said projection so that movement of said operating lever moves said projection over said cam portion thereby to move said arm about its pivot between closed and open circuit positions, said spring being arranged to apply a component of force to said arm biasing said arm longitudinally in a direction from said pivot toward said movable end, current responsive means for operating said latching means to release said pivot upon the occurrence of a predetermined high current whereupon said arm is first pivoted by said spring ROBERT 'r. CASEY.

References Cited in the flle of this patent UNITED 'STATLI'ES PATENTS Number Name Date 2,300,202 Butler Oct. 27, 1942 2,318,987

Butler May 11, 1943 

